CN113749825A

CN113749825A - Frame type bone joint prosthesis and preparation method and application thereof

Info

Publication number: CN113749825A
Application number: CN202110312644.4A
Authority: CN
Inventors: 欧阳宏伟; 吴宏伟
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2020-07-14
Filing date: 2021-03-24
Publication date: 2021-12-07
Anticipated expiration: 2041-03-24
Also published as: CN113749825B

Abstract

The invention provides a frame type bone joint prosthesis and a preparation method and application thereof, the prosthesis comprises a frame structure which is completely matched with the defect shape of a reconstructed part and can be obtained by a 3D printing technology, a gel preparation for promoting bone joint regeneration is covered on the outer surface of the prosthesis, and meanwhile, the frame structure is also provided with a grid layer.

Description

Frame type bone joint prosthesis and preparation method and application thereof

The present invention claims priority from the application of the invention patent having application date of 14/07/2020, application number CN202010672800.3, entitled "a 3D printed frame-type bone or bone joint prosthesis".

Technical Field

The invention relates to the technical field of bone joint prostheses, in particular to a frame type bone joint prosthesis and a preparation method and application thereof.

Background

The repair and reconstruction of massive bone or bone joint defects caused by inflammation, tumor and trauma is a great challenge in clinical treatment at present, and for example, improper treatment and repair can cause serious dysfunction and medical burden. The main treatment methods at present comprise autologous bone transplantation, allogeneic bone transplantation, bone cement filling, joint prosthesis replacement and the like, and have corresponding defects and shortcomings. Mainly has the problems of insufficient autologous bone source, new wound and defect, non-integration of allogeneic bone and autologous bone, occasionally high pressure in a bone marrow cavity caused by bone cement filling, fracture, infection, looseness and the like of a joint prosthesis. Therefore, establishing more advanced repair strategies for massive bone or osteoarticular defects is of great practical significance.

Tissue engineering techniques have become one of the effective potential options for repairing the bone, cartilage and osteochondral interfaces in recent years. The tissue engineering and repair regeneration technology is expected to realize in-vivo in-situ regeneration of large bone joints, becomes living tissues with blood circulation, and can overcome the defects of the method. However, in the process of realizing regeneration of massive bone or bone joint tissues, a scaffold with mechanical strength is needed to fill the bone defect part and provide a local regeneration environment. Clinical trials have now demonstrated that metallic stents are the dominant candidate, and some non-metallic stents are included. However, due to the great individual difference of clinical large-block bone or bone joint defect parts and volumes and the considerable complexity of articular cartilage tissues, an effective large-block bone or bone joint defect repair and regeneration strategy is not established yet. Therefore, further optimization of the framework structure and mechanical properties of the bone or bone joint prosthesis is urgently needed, and a tissue engineering model capable of effectively repairing massive bone or bone joint defects and inducing bone cartilage regeneration is established, so that the prosthesis and regenerated bone tissues are integrated, and complete repair of massive bone or bone joint defects is realized.

CN110215318A discloses an artificial joint prosthesis that utilizes 3D printing technique to prepare, including porous layer, compact layer and embedding layer, adopt novel porous bionical biomaterial, through 3D printing, prepare and operate the good artificial joint prosthesis of position form fitting nature. However, the cartilage cells are cultured in vitro through the porous layer to obtain the articular cartilage surface, and the self bone tissue is filled by adding the macroporous structure on the compact layer, so that the artificial joint prosthesis and the surrounding bone tissue grow into a whole to realize the bone defect reconstruction. Not only is the operation complicated, but also the risk is larger because of uncertain factors existing in the in vitro culture of the chondrocytes.

At present, no related report exists for completing synchronous replacement and in-situ regeneration of large bones or bone joints by adopting the combination of a frame type bone joint prosthesis and hydrogel for promoting bone joint regeneration so as to realize bone joint defect repair.

Disclosure of Invention

In order to solve the problems, the invention provides a frame type bone joint prosthesis, which comprises a frame structure which is completely matched with the defect shape of a reconstructed part, and a gel preparation for promoting bone joint regeneration is covered on the outer surface of the prosthesis, when the prosthesis is implanted into a human body to replace a bone joint, the frame structure provides instant mechanical support, an osteogenic formula contained in the gel preparation effectively promotes the bone joint regeneration, and a tissue engineering bone regeneration technology is applied to solve the problems of mechanical stability and rapid bone regeneration, so that the prosthesis of the frame structure is integrated with the bone or the bone joint regeneration into a movable embedded bone tissue, and the problem of repairing massive bone or bone joint defects is effectively solved.

On one hand, the invention provides a frame type bone joint prosthesis, which comprises an upper section, a middle section and a lower section, wherein the upper section is a joint cartilage layer, the middle section is a backbone and the lower section is a medullary cavity rod; the articular cartilage layer and the backbone are in a frame type structure; the outer surface of the prosthesis is covered with a gel preparation for promoting the regeneration of bone joints; the frame structure of the prosthesis is completely matched with the defect shape of the reconstruction part.

The bone joint prosthesis framework provided by the invention is designed according to the human joint skeleton structure, and can realize the complete consistent matching of the defect shape of the reconstructed part by adopting a 3D printing technology and the like.

The framework structure of a bone or bone joint prosthesis provides sufficient mechanical support and bone regeneration space.

Further, the gel preparation covered on the outer surface of the prosthesis comprises a mixture of hydrogel and autologous bone marrow or crushed bone particles; the hydrogel comprises a biological scaffold material, a bone marrow mesenchymal stem cell osteogenesis inducer, a bone regeneration additive and a photoinitiator, wherein the biological scaffold material comprises any one or more of GelMA, SilkMA, hyaluronic acid, chitosan and HANB.

The hydrogel provided by the invention can be natural biomaterials such as gelatin, silk, hyaluronic acid, chitosan and the like, and the biomaterials are subjected to group modification to form methacrylic anhydride groups (-MA) or nitrosobutylamide groups (N- (2-aminoethyl) -4- (4- (hydroxymethyl) -2-methoxy-5-nitrosophenoxy) butanamide-NB). Such as GelMA derived from gelatin, SilkmA derived from silk, hyaluronic acid, and HANB derived from chitosan. The modified biomaterial can be spontaneously crosslinked to form hydrogel under the conditions of taking lithiumphenyl-2,4, 6-trimethylbenzylphosphinate (LAP) as an initiator and ultraviolet irradiation.

The hydrogel is a biological material with good biocompatibility, can be used as a stent or a carrier, and can coat cells, growth factors, medicines or other physiologically active substances on the surface of a graft. On one hand, the cell and the growth factor are fixed, so that the cell and the growth factor are not easy to lose. On the other hand, the sustained-release tablet can play a role in sustained release of growth factors, medicaments and the like and prolong the action time of the medicaments.

The purpose of adding the autologous bone marrow or the crushed bone particles is to increase the specific gravity of the autologous tissue and cells, adopt the autologous tissue more, reduce the potential inflammatory reaction brought by biological materials, promote rapid regeneration and healing, and simultaneously, the hydrogel can fill pores, load and release regeneration active substances, and fix the autologous bone marrow and the crushed bone particles in the original positions.

Further, the volume ratio of the hydrogel to the autologous bone marrow or the crushed bone granule tissues is 1: 2; the biological scaffold material is 5% of GelMA or 25% of SilkMA.

Experiments prove that when the volume ratio of the hydrogel to the autologous bone marrow or the crushed bone granule tissue is 1:2, the synergistic effect of the hydrogel and the autologous bone marrow or the crushed bone granule tissue can be better exerted, and the bone regeneration is promoted.

Further, the bone marrow mesenchymal stem cell osteogenesis inducer comprises 100mmol/L beta-glycerophosphate, 10^- ³Dexamethasone in mol/L, vitamin C in 500ug/ml, and zoledronic acid in 1 mg/ml; the bone regeneration additive comprises 3mg/ml bone morphogenetic protein BMP-2, 30ug/ml fibroblast growth factor, 3ug/ml vascular endothelial growth factor and 30mg/ml stem cell culture freeze-dried powder; the photoinitiator was 0.5% LAP.

Although there are also some reports on agents for promoting the formulation of osteogenesis, such as active osteogenesis-promoting ingredients such as dexamethasone, and growth factors such as BMP; however, a large number of experiments prove that the single osteogenic component can not effectively promote bone regeneration; the BMP is used as a growth factor for promoting the strongest osteogenesis activity, and the use of the super-physiological dose can easily cause ectopic osteogenesis and bone absorption of immature bone, and can easily cause the reduction of the mechanical property of regenerated bone; moreover, the maintenance time of osteogenic activity is short by only using growth factors; simple use of drugs containing osteogenic activity also tends to produce local cumulative toxicity.

The invention adopts a mode of combining the active substance and the growth factor, the active substance and the growth factor have the function of synergistically enhancing osteogenesis, and meanwhile, the hydrogel which has good biocompatibility and can realize crosslinking by illumination is used as a carrier, so that the operation is simple, the release time of the growth factor and the active substance can be delayed, the action time of promoting bone regeneration is prolonged, and the bone regeneration is effectively promoted.

The prosthesis provided by the invention can be made of medical metal, high-molecular synthetic material, natural material, bionic biological material or inorganic material and the like. In view of facilitating 3D printing and the like, the prosthesis material can be preferably a medical metal material, such as tantalum metal and titanium alloy, and can provide sufficient mechanical support; or high molecular synthetic materials such as polylactic acid, PEEK, polycaprolactone, poly-beta-hydroxybutyric acid, polybutylene succinate, polyvinyl alcohol and the like; in addition, natural materials such as silk, chitosan, gelatin and the like can be selected, bionic biological materials with excellent biological safety, biological activity and mechanical property matched with human bones and some inorganic materials can be selected.

Further, the prosthesis is made of any one or more of titanium alloy, tantalum metal, polylactic acid or PEEK.

In some forms, the prosthesis is made from a titanium alloy, PEEK, or polylactic acid material.

Researches prove that the titanium alloy has higher cell activity, good biocompatibility, strong oxidation resistance, good creep resistance, light weight and high strength, can provide lifelong skeleton or bone joint mechanical support for patients, and is more suitable for being used as a prosthetic material.

The PEEK polyether-ether-ketone is a special engineering resin material with excellent properties of high temperature resistance, self lubrication, hydrolysis resistance, easy processing, high mechanical strength and the like, and is a very good artificial bone material due to the high strength and low dissolution of the PEEK and the good compatibility of the PEEK and a human body.

The polylactic acid is a biodegradable material and has better in vitro cell activity, can promote the growth and repair of human bones and cartilages after the bone joint prosthesis is implanted into a human body, and gradually finishes the degradation of the prosthesis in the process of repairing the human bones and the cartilages until the complete repair of the large bone joint defect of the human body. The polylactic acid has better in-vitro cell activity and more proper degradation speed, so the polylactic acid can also be used for prosthetic materials.

Further, the prosthesis is made of a titanium alloy.

Further, the inner surface and/or the outer surface of the prosthesis are covered with a mesh layer.

The mesh coverage of the inner surface and the outer surface of the skeleton or the bone joint prosthesis can provide a relatively isolated and protected growth environment for bone regeneration, and meanwhile, the layer of the mesh structure can exchange nutrition with peripheral tissue fluid and is also suitable for blood vessel growth, and new bone tissues can be attached to the surface of the mesh for growth.

Furthermore, the aperture of the grid layer is 0.3mm, the diameter of the filament is 0.3mm, and the thickness of the grid layer is 0.3 mm.

A large number of experiments prove that the appropriate porosity of the grid layer is more favorable for the regeneration of chondrocytes. The proper mesh layer aperture can realize better isolation protection effect, does not hinder nutrient exchange with peripheral tissue fluid, is also suitable for blood vessel ingrowth, and helps the new bone tissue to be firmly attached to the surface of the mesh for growth.

Further, the frame of the bone or bone joint prosthesis is composed of a plurality of transverse and longitudinal beams, each beam having communication holes.

The transverse and longitudinal spars together form a lattice-shaped framework for a bone or bone joint prosthesis. Each column beam is provided with a communication hole which can enable the prosthesis and the new bone to be better integrated into a whole and mutually support in mechanics.

Furthermore, the frame of the prosthesis is a lattice frame and consists of column beams, the thickness of each column beam is consistent with that of cortical bone to be replaced, and each column beam is provided with a communication hole; the backbone is in a cylindrical shape, and a hole with the aperture of 0.6mm is reserved in the middle of the corresponding grid layer on the outer surface of the square frame of the backbone; the shape of the articular cartilage layer is consistent with the shape structure of the joint to be replaced, an inner layer grid layer covers the framework of the articular cartilage layer, and the inner layer grid layer and the outer surface grid layer of the prosthesis form a transitional layer of the articular cartilage layer; the aperture of the inner layer grid layer of the migration layer is 0.3mm, the filament diameter is 0.3mm, and the thickness is about 0.3 mm; the medullary cavity rod is in a hollow cylinder shape, and the outer surface of the cylinder is in a point-shaped frosted structure; transverse communicating holes are distributed in the marrow cavity rod in the vertical direction.

In some forms, the frame of the bone or bone joint prosthesis is a checkered frame, the squares being 10mm on a side; wherein the column beam is a square column beam, and the thickness of the column beam is consistent with the thickness of cortical bone to be replaced; the transverse column beam is provided with communicating holes in the vertical direction, the longitudinal column beam is provided with communicating holes in the horizontal direction, the aperture of the communicating holes of the column beam is 0.3mm, and the hole interval is 0.5 mm.

The square grid frame has the square side length of 10mm and the proper square grid size, so that the framework structure of the bone or bone joint prosthesis can not only ensure to provide enough instant mechanical support, but also provide enough regeneration space of bones or cartilages.

The thickness of the column beam is consistent with the thickness of the cortical bone to be replaced, so that the size of the prosthesis is more matched with the defect shape of the reconstruction position, wherein the thickness of the column beam of the articular cartilage layer framework of the bone joint prosthesis is consistent with the thickness of the cortical bone of the joint to be replaced.

Each column beam is provided with a communication hole vertical to the direction of the column beam, so that the transverse column beam is provided with a communication hole vertical to the column beam, and the longitudinal column beam is provided with a communication hole horizontal to the column beam. The proper aperture and the hole spacing of the column-beam communication holes can ensure sufficient instant mechanical support at the initial stage of new implantation when the prosthesis is better integrated with the new bone.

In some forms, the shaft of the bone or bone joint prosthesis is cylindrical in shape with a diameter of 7 mm; a hole with the aperture of 0.6mm is reserved in the middle position of the corresponding grid on the grid layer on the outer surface of the square grid frame of the backbone; the thickness of the square column beam is 1-5 mm.

The size of the diaphysis can be adjusted correspondingly according to the shape of the large defective bone or bone joint, wherein the diaphysis is preferably cylindrical and has the diameter of 7 mm; wherein the bone joint prosthesis has a diaphysis length of preferably 25mm and can support and assist the growth of articular cartilage.

The thickness of the square column beam can be preferably 1-5 mm, and sufficient instant mechanical support is guaranteed to be provided.

The framework of the articular cartilage layer, the grid layer on the inner surface of the framework and the transitional layer on the outer surface of the framework jointly form a porous reticular support structure of the articular cartilage layer, the porous reticular support structure simulates a bone cartilage interface and a cancellous bone area of a human joint, bone can grow inside and outside the porous structure except for providing enough mechanical support, and cartilage tissues can be regenerated depending on a new bone interface layer.

In some embodiments, the inner mesh layer of the traveling layer has a pore size of 0.3mm, a filament diameter of 0.3mm, and a thickness of about 0.3 mm.

The migration layer is designed in a porous grid shape, and the migration layer is specially designed and is suitable for the integrated growth of the interface of cartilage and bone.

In some forms, the intramedullary rod of the bone joint prosthesis is in the shape of a cylinder with a hollow middle, 25mm long and 5mm diameter; the outer surface of the cylinder is of a point-shaped frosted structure; transverse communicating holes are distributed in the vertical direction of the medullary cavity rod and can be used for fixing the medullary cavity rod.

The lower section medullary cavity rod is a part extending into the medullary cavity of the normal diaphysis and is a hollow cylinder made of solid material. The point-shaped frosted structure on the outer surface of the pulp cavity handle can facilitate the bone growth and integration of the surface and the inner wall of the pulp cavity. The transverse communication holes can be used for installing fixing screws to further fix the bone joint prosthesis.

In some embodiments, the intramedullary canal shaft is 25mm long, 5mm in diameter and 1.5mm thick. The outer diameter of the medullary cavity rod is consistent with the inner diameter of the medullary cavity of a person needing replacement, and the outer diameter can be preferably 5 mm; the diameter of the transverse row of communicating holes may preferably be 1.5 mm.

The lower part medullary cavity rod is a hollow cylinder, the length of the cylinder is 25mm, the thickness of the cylinder is 1.5mm, and the inner diameter of the cylinder is the sum of the outer diameter of the medullary cavity rod and the thickness of the cylinder.

In another aspect, the present invention provides a method for covering the outer surface of a prosthesis with hydrogel as described above, comprising the steps of: mixing the hydrogel with autologous bone marrow or crushed bone grain tissues according to the volume ratio of 1:2, uniformly injecting the mixture onto the surface of the stent by using an injector, and irradiating the colloid by using ultraviolet light for 10 seconds while injecting.

In a further aspect, the invention provides the use of a prosthesis as described above for achieving simultaneous replacement and regeneration of a bone joint.

After the bone joint prosthesis provided by the invention is implanted into animals and human bodies for replacement surgery, the bone joint regeneration function can be exerted, so that the replaced joint can obtain instant mechanical stability and simultaneously regenerate corresponding bone and cartilage tissues with living tissue blood circulation in situ, and the aim of synchronous replacement and regeneration of the bone and the joint at the defect part is fulfilled.

A large number of animal experiments are carried out at present, but the preferred application scene of the bone joint prosthesis provided by the invention is the treatment of bone joint diseases of a human body, the secondary application scene is the treatment of bone joint diseases of pets, and the invention also comprises other application scenes suitable for the strategy.

A large number of animal experiments prove that the bone joint prosthesis provided by the invention can really realize the purpose of synchronous replacement and regeneration of the bone and the joint at the defect part, and has good clinical application prospect.

The frame type bone joint prosthesis provided by the invention has the following beneficial effects:

1. creatively takes a 3D printing frame type bone joint prosthesis as a basic technical means, combines a gel preparation for promoting the growth of bones, and applies a tissue engineering technology for rapid bone joint regeneration to realize the regeneration and repair of large-section bone joint defects.

2. The frame prosthesis may provide sufficient effective immediate mechanical support and space for bone regeneration.

2. The gel preparation for promoting the growth of the skeleton is covered on the surface of the frame type prosthesis in a mode of combining the active substance and the growth factor, the active substance and the growth factor have the effect of synergistically enhancing osteogenesis, and meanwhile, the hydrogel which is good in biocompatibility and can be crosslinked by illumination is used as a carrier, so that the operation is simple, the release time of the growth factor and the active substance can be delayed, the action time of promoting the regeneration of the skeleton is prolonged, and the regeneration of the skeleton is effectively promoted.

3. The inner surface and the outer surface of the prosthesis of the frame structure are covered by fine meshes, and a proper aperture ratio is selected, so that a relatively isolated and protected growth environment is provided for bone regeneration, nutrition exchange can be carried out between the prosthesis and peripheral tissue fluid, the prosthesis is also suitable for blood vessel growth, and new bone tissues can be attached to the surface of a grid for growth.

4. The joint surface has a specially designed migration layer suitable for the integrated growth of cartilage and bone interface.

5. The repair and reconstruction of massive bone or bone joint defects are solved in a one-stop mode, and the problem of secondary repair operation due to limited service life of the prosthesis is avoided.

6. The prosthesis shape is completely matched with the defect shape of the reconstructed part, and the prosthesis is formed by 3D printing of the most appropriate material, the mutual relation among the support structure, the mechanical property and the bone regeneration is further optimized, the prosthesis has very important theoretical significance for establishing a tissue engineering model which can effectively repair cartilage injury and induce the bone cartilage regeneration, the purpose of synchronous replacement and regeneration of the bone and the joint of the defect part is realized, and the problem of repairing the defect of the large bone joint is effectively solved.

Drawings

FIG. 1 is a disassembled view of the structures of the layers of the frame-type bone joint prosthesis in example 1

FIG. 2 is a schematic view showing the outer configuration of a frame-type bone joint prosthesis according to example 1

FIG. 3 is a cross-sectional view taken along line A-A of the frame-type bone joint prosthesis in example 1

FIG. 4 is a B-B sectional view of the frame-type bone joint prosthesis in example 1

FIG. 5 is a C-C sectional view of the frame-type bone joint prosthesis in example 1

FIG. 6 is a schematic view of a frame-type bone joint prosthesis prepared from titanium alloy, PEEK and polylactic acid according to example 1

FIG. 7 is a schematic representation of a frame-type bone joint prosthesis made of titanium alloy, PEEK, and polylactic acid according to example 1

FIG. 8 is a partial photograph of the hydrogel-covered framework-type bone joint prosthesis of example 1

FIG. 9 is a graph showing the experimental results of the effect of three different hydrogel formulations on osteoinductive activity in example 2

FIG. 10 is a photograph of a portion of the prosthesis covered with hydrogel at volume ratios of 1:0 and 1:2 in example 3, respectively

FIG. 11 is a photograph of the procedure for performing a proximal replacement rabbit humerus procedure on the frame-type bone joint prosthesis of example 4

FIG. 12 is a photograph showing that the photo-cured hydrogel mixed with autologous crushed bone particles and bone marrow on the surface of the stem of the prosthesis in example 4

FIG. 13 is a graph showing the results of X-ray examination performed 4-8 weeks after implantation of the three prostheses of example 7

FIG. 14 is a graph showing the results of CT examination conducted 8 weeks after the control group and the 25% SilkMA + osteogenic Induction + bone regeneration hydrogel group in example 7

Detailed Description

In the following, preferred embodiments of the present invention will be described in further detail with reference to the accompanying drawings, it being noted that the following embodiments are intended to facilitate understanding of the present invention without any limitation thereto. The raw materials and equipment used in the examples of the present invention are known products and obtained by purchasing commercially available products.

Example 1A frame-type bone joint prosthesis according to the invention

The present embodiment provides a frame-type bone joint prosthesis as shown in fig. 1, 2, 3, 4 and 5, wherein fig. 1 is an exploded view of the various layered structures of the frame-type bone joint prosthesis; FIG. 2 is a schematic structural outline of a frame-type bone joint prosthesis; FIG. 3 is a cross-sectional view A-A of the frame-type bone joint prosthesis; FIG. 4 is a B-B cross-sectional view of the frame-type bone joint prosthesis; fig. 5 is a C-C section view of a frame-type bone joint prosthesis.

The material of the frame-type bone prosthesis of this embodiment may be made of titanium alloy, tantalum metal, polylactic acid, PEEK material, etc., and this embodiment is preferably made of titanium alloy material.

The frame-type bone joint prosthesis of the embodiment is prepared by 2D printing and comprises an upper section, a middle section and a lower section, wherein the upper section is a joint cartilage layer 10, the middle section is a backbone 1, and the lower section is a medullary cavity rod 11, wherein the inner surface and/or the outer surface of the bone joint prosthesis are/is covered with a grid layer, preferably, the inner surface and the outer surface of the bone joint prosthesis are covered with a grid layer, the bone joint prosthesis comprises an inner surface grid layer 12 and an outer surface grid layer 13, the joint cartilage layer 10 is provided with a cartilage layer framework structure 14, and the backbone 1 is provided with a backbone framework structure 2.

The framework structure 14 of the articular cartilage layer 10 is also covered with a grid layer 15, and the grid layer 15 and the mesh layer 13 on the outer surface of the prosthesis together form a transitional layer 16 of the articular cartilage layer 10.

Preferably, the inner surface mesh layer 12 and the outer surface mesh layer 13 have a pore size of 0.3mm, a filament diameter of 0.3mm and a thickness of 0.3 mm.

Preferably, the inner mesh layer 15 of the traveling layer 16 has a pore size of 0.3mm, a filament diameter of 0.3mm and a thickness of about 0.3 mm.

Preferably, the framework of the articular cartilage layer 10 and the shaft 1 is composed of a plurality of transverse and longitudinal girders 5.

Preferably, the cartilage layer frame structure 14 and the backbone frame structure 2 are both square lattice frames, and the side length of each square 6 is 10 mm; wherein the column beam 5 is a square column beam.

Preferably, the pillar beam 5 is 2mm thick.

Preferably, the transverse column beam is provided with communication holes 7 in the vertical direction, the longitudinal column beam is provided with communication holes 8 in the horizontal direction, the hole diameter of each communication hole is 0.3mm, and the hole interval is 0.5 mm.

Preferably, the outer surface of the backbone frame structure 2 is provided with a grid layer, leaving holes 7 with a diameter of 0.6mm in the middle of the corresponding grid 6.

Preferably, the stem 1 is 25mm long and 7mm in diameter.

Preferably, the medullary cavity rod 11 is in a cylindrical shape with a hollow center, the outer surface of the cylinder 17 is a point-shaped frosted structure 18, and transverse communication holes 19 are distributed in the perpendicular direction of the medullary cavity rod.

Preferably, the medullary cavity rod 11 is 25mm long, 5mm in diameter and 1.5mm in thickness, and the outer diameter of the medullary cavity rod 11 is consistent with the inner diameter of the medullary cavity of the patient needing replacement; the diameter of the transverse communicating holes 19 is 1.5 mm.

Fig. 6 is a schematic diagram of a frame-type bone joint prosthesis prepared by respectively adopting titanium alloy, PEEK and polylactic acid, and fig. 7 is a real object diagram of the frame-type bone joint prosthesis prepared by respectively adopting titanium alloy, PEEK and polylactic acid.

The invention provides a method for covering hydrogel on the outer surface of a frame-type bone joint prosthesis, which comprises the following steps:

(1) preparing a biological scaffold, namely preparing a 25% SilkMA solution as the biological scaffold;

(2) 100mg of zoledronic acid, 10mol of beta-glycerophosphoric acid and 10mol of beta-glycerophosphoric acid are respectively added into 100ml of 25 percent SilkmA solution^-3mol dexamethasone and 50mg vitamin C, and is prepared into the pharmaceutical composition containing 1mg/ml zoledronic acid, 100mmol/L beta-glycerophosphoric acid and 10 mmol/L vitamin C^-3mol/L ofDexamethasone and 500ug/ml vitamin C mixed solution;

(3) and (3) taking 100ml of the mixed solution prepared in the step (2), respectively adding 300mg of bone morphogenetic protein BMP-2, 3mg of fibroblast growth factor, 300ug of vascular endothelial growth factor, 3g of stem cell culture medium freeze-dried powder and 0.5ml of LAP, and uniformly mixing to obtain the hydrogel.

(4) Mixing the hydrogel with the crushed bone particles, uniformly injecting the hydrogel onto the surface of the bracket by using an injector, and irradiating the colloid by using ultraviolet light for 10 seconds while injecting. A partial photograph of the frame-type bone joint prosthesis after covering with hydrogel is shown in fig. 8.

Example 2 formulation selection of hydrogel for promoting regeneration of bone Joint

In this embodiment, the titanium alloy frame-type bone joint prosthesis provided in embodiment 1 is divided into three groups according to different hydrogel formulations, wherein the first group is a control group using a pure GelMA hydrogel, the second group is a group using GelMA hydrogel + osteogenesis inducer, the third group is a group using GelMA hydrogel + osteogenesis inducer + bone regeneration microenvironment additive, the GelMA hydrogel is 5% GelMA hydrogel, and the osteogenesis inducer includes 1mg/ml zoledronic acid, 100mmol/L β -glycerophosphoric acid, and 10 mmol/L β -glycerophosphoric acid^- ³Dexamethasone of mol/L, vitamin C of 500ug/ml, bone regeneration additives including bone morphogenetic protein BMP-2 of 3mg/ml, fibroblast growth factor of 30ug/ml, vascular endothelial growth factor of 3ug/ml, stem cell culture lyophilized powder of 30mg/ml, and LAP of 0.5% as photoinitiator for in vitro osteogenesis induction experiment. Bone marrow mesenchymal stem cells (BMSCs) were cultured on each set of hydrogels for one week, followed by alkaline phosphatase staining and alizarin red staining, respectively, after one week. The results are shown in FIG. 9, and show that BMSCs survived normally on each set of hydrogels, indicating that the hydrogels were not cytotoxic. Comparing the osteogenesis activities of the three groups, it can be seen that the GelMA hydrogel + osteogenesis inducing + bone regeneration enhancing group of the third group has the optimal osteogenesis activity, and the alkaline phosphatase strength is improved by about 50% compared to the conventional osteogenesis inducing activity.

EXAMPLE 3 selection of the volume ratio of hydrogel to autologous bone fragments

This example uses the titanium alloy frame type bone joint prosthesis provided in example 1 and the hydrogel formulation provided in the third group of example 2, wherein the volume ratio of the hydrogel to the self-crushed bone particles is selected to be 1:0, 1:1, 1:2, 1:3 and 1:4, respectively, and the coverage effect of the hydrogel and the self-crushed bone particles on the surface of the prosthesis is examined, and the results are shown in table 1, wherein when the volume ratio is 1:0 and 1:2, respectively, a partial photograph of the frame type bone joint prosthesis covered with the hydrogel is shown in fig. 10.

TABLE 1,

When more autologous tissues are adopted, the rapid regeneration and healing can be promoted. As can be seen from table 1, when only the hydrogel is contained, although the gel is firmly covered and no voids remain, the speed of regenerative healing is affected due to the lack of autologous tissue. When the volume ratio of the hydrogel to the autologous bone marrow or the crushed bone granule tissue is 1:2, the gel covering effect is still good, no gap residue exists, the autologous tissue can accelerate the speed of promoting bone regeneration and healing, the synergistic effect of the hydrogel and the autologous bone marrow or the crushed bone granule tissue can be better exerted, and the bone regeneration is promoted. The volume ratio of hydrogel to autologous bone marrow or crushed bone grain tissue is therefore preferably 1: 2.

Example 4 proximal replacement surgery of a rabbit humerus Using a Framed bone Joint prosthesis

In this embodiment, a titanium alloy frame-type bone joint prosthesis provided in example 1 is used to perform a proximal humeral replacement operation on a new zealand rabbit, wherein the hydrogel includes GelMA hydrogel + osteogenesis inducing hydrogel + bone regeneration hydrogel provided in the third group of example 2, and a photograph of the operation flow is shown in fig. 10, and the specific steps include: new Zealand rabbits were anesthetized intravenously with Sutai 50 according to the instructions and penicillin was administered in 50 ten thousand units intramuscularly before surgery. Prepare skin of operation area, and disinfect skin 3 times with iodine. And laying a sterile hole towel, and fixing the hole towel by a suture. The skin of the surgical area is again disinfected. The round blade longitudinally incises the skin and the subcutaneous fascia at the proximal end of the forelimb of the rabbit, and avoids the subcutaneous great vein. The humerus lateral muscle is longitudinally cut to the humerus surface, the humerus shaft is exposed, the periosteum stripper strips the muscle and the periosteum, and the upper part of the humerus shaft and the shoulder joint capsule are completely exposed. The joint capsule and ligament are severed from the joint capsule near the humeral stop, exposing the humeral head and joint. The soft tissue was stripped along the bone surface, leaving the upper humeral segment completely free, and the humerus was cut off with an electric saw from the middle-upper third. The sterilized titanium alloy frame type prosthesis handle is inserted into the far-end humerus medullary cavity, and the prosthesis is fixed by the cross rod. Mixing prepared iliac bone fragments and bone marrow tissues with SilkMA composite colloid for promoting bone regeneration according to the volume ratio of 2:1, covering the mixture on the surface of the bone marrow tissues, and curing the colloid by ultraviolet light in a hand. A photograph of the photo of the surface light-cured hydrogel mixed with autologous crushed bone particles and bone marrow on the stem of the prosthesis is shown in FIG. 11. The reduction prosthesis is articulated into the glenoid, the joint capsule is fixed on the outer side of the greater tubercle of the humerus prosthesis by sewing with a 7-gauge line, and the joint capsule at other parts is also closed. The humerus muscle and skin are sutured layer by layer, and the incision is closed. After the animals revive, the animals are fed into cages for feeding.

EXAMPLE 5 selection of materials for prosthesis preparation

Respectively adopting polylactic acid, PEEK, poly-beta-hydroxybutyric acid, poly butylene succinate, polyvinyl alcohol, titanium alloy and tantalum metal material samples to carry out in-vitro cell bioactivity experiments and degradation time measurement. The in vitro cell bioactivity test comprises aseptically collecting resuscitated mouse femur bone-derived osteoblast, placing in DMEM medium containing fetal calf serum with volume fraction of 0.1 and 0.1% of cyan/streptomycin, and culturing at 37 deg.C in CO2 incubator with volume fraction of 0.05. Changing the solution every 3 days, digesting with pancreatin after the cells grow to confluence, and stopping digestion with fresh culture medium containing serum to obtain cell suspension. Respectively taking polylactic acid, polycaprolactone, titanium alloy and tantalum metal material samples, placing the samples into a 24-hole culture plate after autoclaving, adding 1ml of the cell suspension into each hole for inoculation, placing the inoculated samples into a CO2 cell culture box with the temperature of 37 ℃ and the volume fraction of 0.05 for culture, taking the samples out after 3 days, and measuring the number of cells adhered to the surfaces of the samples by using a tetramethylazoazolium salt trace enzyme reaction colorimetric method (MTT method), wherein the results are shown in Table 2. The degradation time was measured by soaking the xerogel in a phosphate buffer solution at ph7.4 and measuring the weight loss at regular intervals.

TABLE 2 in vitro cell Activity and degradation time determination of different prosthetic materials

As can be seen from Table 2, when in vitro cell biological culture is carried out on polylactic acid, PEEK, titanium alloy and tantalum metal, the obtained cell activity is higher, and meanwhile, the polylactic acid has degradability and proper degradation time; the PEEK, the titanium alloy and the tantalum metal have good biocompatibility, strong oxidation resistance and high strength, and can provide lifelong skeleton or bone joint mechanical support for patients, so the titanium alloy, the PEEK and the polylactic acid are preferably used as preparation materials of 3D printing frame type bone joint prostheses, the titanium alloy is most preferably used as a support, the strength is sufficient, the compatibility is good, and the total cell amount and the survival rate are high.

Example 6 selection of mesh layer pore size

The frame-type bone joint prosthesis provided in example 1 was prepared using a polylactic acid material, wherein the mesh layer had a pore size of 0.1mm, 0.3mm, 0.5mm, 1mm, and was inoculated with human chondrocytes (pnuosai, CP-H096) at an inoculum size of 2 × 10⁵DMEM medium was used as a basal medium, and serum replacement and growth factors were added for culture, and after 15 days, the proliferation ability of chondrocytes in the lattice layer of the prosthesis was measured, and the results are shown in table 3.

TABLE 3 Effect of different mesh layer pore sizes on chondrocyte proliferation

Experimental group	Pore size of mesh layer	Total cell mass after 15 days (10)⁶)	Cell viability (%)
				1	0.1mm	1.02	63.1
2	0.3mm	4.95	96.5
				3	0.5mm	4.88	96.1
4	1mm	4.91	96.2

As can be seen from Table 3, when the pore size of the mesh layer of the prosthesis is 0.1mm, the cartilage cells are not proliferated because of the small pore size, and the total cell amount and the cell survival rate after 15 days are low; when the pore diameter of the mesh layer of the prosthesis is 0.3mm, 0.5mm and 1mm, the proliferation condition of the chondrocytes is ideal, and the total cell amount and the cell survival rate after 15 days are high; the inner surface and the outer surface of the prosthesis are covered by fine grids comprehensively, a relatively isolated and protected growth environment can be provided for bone regeneration, therefore, a grid layer with the aperture of 0.3mm is more suitable, and the porosity is more favorable for regeneration of chondrocytes.

EXAMPLE 7 bone growth of Framed bone Joint prosthesis implanted in rabbits

In the embodiment, 36 healthy and clean new zealand white rabbits of 4-5 months old are selected and randomly divided into four groups, 9 rabbits in each group are respectively implanted with prosthesis replacement of left tibia and left humerus joints, the frame-type titanium alloy bone prosthesis, the polylactic acid bone prosthesis, the tantalum metal bone joint prosthesis and the polylactic acid bone joint prosthesis provided in the embodiment 1 are respectively implanted, the pore diameter of a grid layer of the prosthesis is 0.3mm, and the surface of the prosthesis is covered with the GelMA hydrogel + osteogenesis induction + bone regeneration hydrogel provided in the third group of the embodiment 2. The rabbits were sacrificed at 1, 3, and 5 months after the operation, 3 rabbits were obtained at each time point, and hard tissue sections were stained and observed under a microscope to calculate the bone formation rate at the bone interface of the prosthesis and the bone integration rate between the prosthesis and the bone interface, and the results are shown in tables 4 and 5, in which one of the accidents of the prosthesis fracture occurred is shown in table 6. Wherein: new bone formation rate (%) - (new bone tissue area/total area × 100%; bone binding rate (%) — bone-prosthesis osseointegration length/total length of bone-prosthesis interface × 100%.

TABLE 4 comparison of newborn bone formation rates

Experimental group	Prosthesis type	4 weeks (%)	8 weeks (%)	12 weeks (%)
					1	Titanium alloy bone joint prosthesis	26.98	80.35	96.43
2	Polylactic acid joint prosthesis	15.79	69.46	94.45
					3	PEEK bone joint prosthesis	19.93	77.59	94.48

TABLE 5 comparison of bone-bonding rates

Experimental group	Prosthesis type	4 weeks (%)	8 weeks (%)	12 weeks (%)
					1	Titanium alloy bone joint prosthesis	29.25	81.19	99.12
2	Polylactic acid joint prosthesis	14.18	71.27	98.33
					3	PEEK bone joint prosthesis	20.51	79.41	98.47

TABLE 6 accidents after prosthesis implantation

Experimental group	Prosthesis type	Post-implantation accidents
			1	Titanium alloy bone joint prosthesis	Without breaking
2	PEEK bone joint prosthesis	Without breaking
			3	Polylactic acid bone joint prosthesis	A break occurred

As can be seen from tables 4 and 5, after the frame-type bone joint prosthesis provided by the invention is implanted into a rabbit body, the bone growth speed of the titanium alloy and PEEK bone joint prosthesis is higher at 4 weeks and 8 weeks, but at 12 weeks, the three prostheses, namely the titanium alloy bone joint prosthesis, the polylactic acid bone joint prosthesis and the PEEK bone joint prosthesis, can basically complete bone growth, the new bone formation rate and the bone combination rate reach over 90 percent, and the prosthesis with the frame structure and bones or bone joints can be regenerated and integrated into a movable embedded bone tissue.

As can be seen from table 6, there is an unexpected risk of fracture for bone prostheses made with polylactic acid, while prostheses made with titanium alloys and PEEK are stronger and safer.

Example 8 Effect verification of bone growth promoting hydrogel

In this embodiment, a titanium alloy frame-type bone joint prosthesis provided in example 1 is used to perform proximal humeral replacement surgery on a new zealand rabbit, wherein a gel preparation covered on the surface of the prosthesis includes a mixture of hydrogel and autologous bone marrow or crushed bone particles in a volume ratio of 1:2, the hydrogel provided in the third group of example 2 is hydrogel + osteogenesis inducing + bone regeneration hydrogel, the hydrogel respectively selects 5% of GelMA + osteogenesis inducing + bone regeneration hydrogel or 25% of SilkMA + osteogenesis inducing + bone regeneration hydrogel, a group of simple prostheses without hydrogel is additionally provided as a control group, X-ray examination is performed 4-8 weeks after the three groups of prostheses are implanted, and the result is shown in fig. 12; and CT examination was performed 8 weeks after the control group and the 25% SilkMA + osteogenesis inducing + bone regeneration hydrogel group, and the results are shown in FIG. 13.

As can be seen from fig. 12, the left 1 is a pure prosthesis group without hydrogel, and after 8 weeks, only a very small amount of new bones exist, so that the prosthesis and the bone joint are difficult to regenerate and fuse into a whole; the left 2 is 5% GelMA + osteogenesis inducing + bone regeneration group hydrogel, and after the hydrogel is implanted for 4 weeks, a large amount of new bone tissues around the prosthesis, especially on the right side, can be seen; the left 3 is 25% SilkMA + osteogenesis inducing + bone regeneration hydrogel, and a large amount of new bone tissues around the prosthesis can be seen after the hydrogel is implanted for 4 weeks; the left 4 is 25% SilkMA + osteogenesis inducing + bone regeneration hydrogel, implanted for 8 weeks, and complete bone regeneration is achieved around the prosthesis. Therefore, the hydrogel prepared by 5% of GelMA or 25% of SilkMA can obviously promote bone regeneration, and has very obvious effect compared with a control group.

As can be seen from fig. 13, the left image is a control group, and when a pure stent group is adopted, the metal stent is completely exposed in the CT three-dimensional reconstruction image; the right side is 25% of SilkMA + osteogenesis induction + bone regeneration group, so that the shadow of the metal bracket cannot be seen, the surface of the metal bracket is full of bones, and the surface of the metal bracket is wrapped by bone shells in the longitudinal section. Therefore, 25% of SilkMA + osteogenesis induction + bone regeneration hydrogel has obvious composite bone growth promoting effect.

Although the present invention is disclosed above, the present invention is not limited thereto. For example, the application range of the medicine can be expanded. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A frame type bone joint prosthesis is characterized by comprising an upper section, a middle section and a lower section, wherein the upper section is a joint cartilage layer, the middle section is a backbone, and the lower section is a medullary cavity rod; the articular cartilage layer and the backbone are in a frame type structure; the outer surface of the prosthesis is covered with a gel preparation for promoting the regeneration of bone joints; the frame structure of the prosthesis is completely matched with the defect shape of the reconstruction part.

2. The prosthesis of claim 1, wherein the gel formulation covering the outer surface of the prosthesis comprises a mixture of hydrogel and autologous bone marrow or crushed bone particles; the hydrogel comprises a biological scaffold material, a bone marrow mesenchymal stem cell osteogenesis inducer, a bone regeneration additive and a photoinitiator, wherein the biological scaffold material comprises any one or more of GelMA, SilkMA, hyaluronic acid, chitosan and HANB.

3. The prosthesis of claim 2, wherein the hydrogel to autologous bone marrow or morselized bone tissue is present in a 1:2 volume ratio; the biological scaffold material is 5% of GelMA or 25% of SilkMA.

4. The prosthesis of claim 3, wherein the osteogenesis inducing agent for mesenchymal stem cells of bone marrow comprises 100mmol/L of β -glycerophosphate, 10^-3Dexamethasone of mol/L, vitamin C of 500ug/ml, zoledronic acid of 1 mg/ml; the bone regeneration additive comprises 3mg/ml bone morphogenetic protein BMP-2, 30ug/ml fibroblast growth factor, 3ug/ml vascular endothelial growth factor and 30mg/ml stem cell culture freeze-dried powder; the photoinitiator was 0.5% LAP.

5. A prosthesis as claimed in any one of claims 1 to 4 wherein the prosthesis is made from any one or more of titanium alloy, tantalum metal, polylactic acid or PEEK.

6. The prosthesis of claim 5, wherein the inner surface and/or the outer surface of the prosthesis are covered with a mesh layer.

7. The prosthesis of claim 6, wherein the mesh layer has a pore size of 0.3mm, a filament diameter of 0.3mm, and a thickness of 0.3 mm.

8. The prosthesis according to claim 7, wherein the frame of the prosthesis is a lattice frame consisting of column beams, the thickness of the column beams is consistent with the thickness of cortical bone to be replaced, and each column beam is provided with a communication hole; the backbone is in a cylindrical shape, and a hole with the aperture of 0.6mm is reserved in the middle of the corresponding grid layer on the outer surface of the square frame of the backbone; an inner layer grid layer covers the framework of the articular cartilage layer, and the inner layer grid layer and the outer surface grid layer of the prosthesis form a transitional layer of the articular cartilage layer; the aperture of the inner layer grid layer of the migration layer is 0.3mm, the filament diameter is 0.3mm, and the thickness is about 0.3 mm; the medullary cavity rod is in a hollow cylinder shape, and the outer surface of the cylinder is in a point-shaped frosted structure; transverse communicating holes are distributed in the marrow cavity rod in the vertical direction.

9. A method of covering an outer surface of a prosthesis with a hydrogel according to any of claims 1 to 8, comprising the steps of: mixing hydrogel with autologous bone marrow or crushed bone granule tissue according to the volume ratio of 1:2, uniformly injecting the mixture onto the surface of the stent by using an injector, and irradiating the colloid by using ultraviolet light for 10 seconds while injecting.

10. Use of a prosthesis according to any of claims 1-8 for simultaneous replacement and regeneration of a bone joint in a human or animal.